Add the following lines in the default Apache virtual host configuration file at /opt/bitnami/apache2/conf/bitnami/bitnami.conf, inside the default VirtualHost directive, so that it looks like this:
<VirtualHost _default_:80>
DocumentRoot "/opt/bitnami/apache2/htdocs"
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^/(.*) https://%{SERVER_NAME}/$1 [R,L]
...
</VirtualHost>
After modifying the Apache configuration files:
Open port 443 in the server firewall.
Restart Apache to apply the changes.